Cost to Diagnose and Fix a Leaky Basement

After even a small amount of rain, our basement floor is much too damp. I don't know if it's from runoff or seepage. I checked for condensation, but the problem is not from the walls. What's the best way to check for foundation problems and is it too late to use a sealant now? Is this going to cost a fortune?

Don G. ~ Norfolk, Virginia

The water may be entering your home's basement from the outside through the seam which is located between the concrete walls and the basement floors. If you live in an area with a high water table, and your basement is surrounded by ground water, the intense hydro-static pressure can push a lot of water through even the smallest of openings in you concrete foundation.

You can seal some of these potentially problematic areas from the inside of your basement, but keep in mind that sometimes this is a problem that must be addressed from the outside of the house. It is important that the outside of the foundation walls are well sealed, using brushed-on foundation tar or a glued-on rubber membrane. In addition to these waterproofing techniques, a drain system can be installed around the footing of the foundation that can divert away any water that gathers against the outside of the basement walls.

Of course it can get expensive to start excavating out your home's foundation, so I would first conduct a thorough investigation of your basement floors. If you find areas where the water if entering into the house, apply a bead concrete sealant to the seam or crack, and see if that stops the leaks. If this simple fix from the inside does not work, you may have to start digging on the outside. Good luck!